I have some reservations about the specification - it looks like there are a lot of caveats to how it can be used. For example, it's allowed in for and for-of loops, but not in for-in loops. Also looks like destructuring will not be allowed.

    using res = getResource(); 
    const { x, y } = res; // ok
    
    using { x, y } = getResource(); // error

There is literally an example for using destructuring in the linked article. So it is supported.

Can you clarify where it indicates it's supported i.e. which specific example? I re read and didn't see it myself, seems others are missing it.

To be fair I don't see it not being supported either by the examples.

    {
      await using { connection } = getConnection();
      // Do stuff with connection
    } // Automatically closed!